注意：此页面搜索的是所有试题
题目内容
（兰州大学-大学英语3）
(4分)I failed in the last exam and only then ___ the importance of studies.
A. I realized
B. I had realized
C. had I realized
D. did I realize
A. I realized
B. I had realized
C. had I realized
D. did I realize
参考答案